Options
Vanselow, Barbara
Estimating total body fat using computed tomography in two dog breeds
2012, Purushothaman, Dharma, Brown, Wendy, Wu, Shubiao, Vanselow, Barbara
Background: Use of computed tomography (CT) in canine obesity research is limited and accuracy of estimated fat is still questioned. Using latest image analysis programs, previous studies in sheep showed a significant correlation between CT-derived and hot carcass measurements. Hence we tested the method in canine research. Objective: To develop an improved research method to estimate body composition including total body fat, lean tissue and bone in two morphologically diverse breeds of dogs. Design: A whole body scan was performed twice (four weeks apart) on six beagles and six greyhounds using Picker UltraZ 2000 CT scanner. They were sedated to the prone position with fore/hind limbs pointing forward and tails tucked in. The individual CT images were taken at 10 mm interval and edited using latest software (OSIRIX) in diacom format to remove extraneous objects within the image. Images were then converted from 16 bit CT image to 8 bit binary image using Image J and rescaled to 256 greyscales using AutoCAT. Boundaries for fat, lean and bone were set to the scales of 20-130, 131-220, and 221-255 respectively. The AutoCAT program then computed the total weight of fat, lean and bone for each dog. CT-derived total body weight was calculated from the sum of fat, lean and bone. Percentages of fat, lean and bone were also calculated. Pearson correlation analysis between CT-derived and measured total body weight were performed separately in two breeds for two scans (CT1, CT2). Significant differences of fat% between breeds were determined using paired t-test. Outcomes: When CT-derived total body weight was compared with measured total bodyweight, both beagles and greyhounds showed a significant correlation (R²=0.99; P=0.000) for both scans. The method also detected a significant breed difference (P=0.000) in the mean fat% for both scans. Conclusion: The proposed method using latest image analysis software programs showed significant correlation between CT-derived and measured total body weight for both the breeds, and the results were reproducible in two scans. The body compositions of different breeds measured by the CT scan were significantly different. Future studies should compare the proposed method with other existing methods used for detecting body composition such as dual-energy X-ray absorptiometry and deuterium oxide dilution.
Flaxseed oil supplementation alters the expression of inflammatory-related genes in dogs
2014, Purushothaman, Dharma, Brown, Wendy, Vanselow, Barbara, Quinn, Kim, Wu, Shubiao
Long chain 'n'-3 fatty acids are beneficial to mammals because of their anti-inflammatory role. However, whether flaxseed oil, which is rich in short chain 'n'-3 fatty acids, has such a role, it has not been extensively examined. This study investigated the supplementation of flaxseed oil on the regulation of genes involved in inflammatory responses such as heat shock proteins ('HSP90' and 'HSP70') and interleukin ('IL1β') in the white blood cells of dogs. Five beagles and 5 greyhounds were supplemented with Melrose® flaxseed oil at the rate of 100 mL/kg food for 21 days. The blood was collected at day 0, 15, and 22 following supplementation. The expression of 3 genes was quantified using real-time polymerase chain reaction. Plasma concentrations of fatty acids such as alpha linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, and arachidonic acid were measured, and their correlations with changes in gene expression were determined. Flaxseed oil supplementation downregulated the expression of 'HSP90' and 'IL1β' in greyhounds but showed no significant effect on these genes in beagles. 'HSP70' remained unchanged in both breeds following the supplementation. Correlations of 'HSP90' and 'IL1β' expression levels with the plasma fatty acid concentrations on day 22 showed a significant negative correlation in greyhounds. Dietary flaxseed oil altered the expression of genes involved in inflammation in white blood cells. Because the expression of the genes may vary in different breeds, it will be useful to consider breed responses to dietary manipulation in canine nutrition management.
Biochemical and Transcriptional Responses to n-3 Fatty Acids in Two Breeds of Dogs
2015, Purushothaman, Dharma, Brown, Wendy, Wu, Shubiao, Vanselow, Barbara
Polyunsaturated fatty acids (PUFA), which include n-3 and n-6 fatty acids, are essential for the health of both humans and dogs. Consequently, the need to include n-3 fatty acids in commercial dog foods is gaining increasing recognition. Fish is a natural source of n-3 fatty acids; however, with the reduction in the global fish stock, alternate sources of n-3 fatty acids are gaining importance, and one such example is flaxseed oil. Besides the inclusion of PUFA in canine food, the need to cater to breed-specific dietary requirements is also recognised. In the light of this knowledge, the current research project investigated the breed differences in the biochemical (changes to plasma fatty acid composition) and transcriptional (changes to white blood cell inflammatory-related gene expression) responses to n-3 fatty acids from two dietary sources in two different breeds of dogs. Beagles and greyhounds were chosen for their differences in morphology and propensity to obesity.
Evaluating changes in body weight gain, nutrient digestibility, inflammatory gene expression and RBC FA following DHA- rich fish oil supplementation in two dog breeds
2012, Purushothaman, Dharma, Brown, Wendy, Wu, Shubiao, Vanselow, Barbara
Background: Previous studies have demonstrated that DHA n-3 FA can reduce obesity by inhibiting adipocyte differentiation. Objective: To investigate the potential of a DHA rich supplement (fish oil; FO) over non DHA (sunflower oil; SF) to reduce weight gain in dogs, when the animals were fed increased dietary energy intakes above maintenance levels (iso-caloric in both groups). The transcriptional, metabolic and phenotypic responses in two dog breeds were assessed. Design: Six beagles and greyhounds were divided equally into two treatment groups (FO and SF). During four weeks, energy intake was increased 20-80% above maintenance level achieved by feeding basal diet (kibble), coconut fat and supplement (FO or SF). Changes to body weight gain (BWG), apparent nutrient digestibility (Dry Matter, Fat, and Gross Energy), red blood cell (RBC) FA levels, White Blood Cell (WBC) inflammatory gene expression levels (HSP90, HSP70 and IL1β) were measured twice: at days 0 and 28. A paired t-test was used to determine significance between time periods, treatments or breeds. Outcomes: BWG in beagles fed FO were significantly higher (P<0.05) than those fed SF. No significant differences in BWG in greyhounds or between breeds were shown. Differences were not seen in apparent nutrient digestibility. HSP90 gene expression was up-regulated in the beagles fed FO (P<0.05), while HSP70 gene down-regulated for both breeds fed SF (P<0.05). A significant breed difference was observed for HSP70 fed SF (P<0.05). RBC EPA levels significantly increased in both breeds fed FO (P<0.05) with no significant difference in DHA levels. Only beagles fed SF showed significant increase in LA, AA (P<0.05). Both breeds fed SF showed significant decrease in GLA (P<0.05). Significant breed differences (P<0.05) were found in RBC FA levels of EPA (FO), LA, GLA and AA (SF). Conclusion: Results from the four weeks trial do not support the potential of DHA n-3 FA to reduce BWG. However, within the same time frame, WBC inflammatory gene expression and RBC FA levels showed differences between treatments and breeds. Therefore breed differences warrant further investigation and future studies should be designed for extended periods with larger datasets.
Whole Body Computed Tomography with Advanced Imaging Techniques: A Research Tool for Measuring Body Composition in Dogs
2013, Purushothaman, Dharma, Vanselow, Barbara, Wu, Shubiao, Butler, Sarah, Brown, Wendy
The use of computed tomography (CT) to evaluate obesity in canines is limited. Traditional CT image analysis is cumbersome and uses prediction equations that require manual calculations. In order to overcome this, our study investigated the use of advanced image analysis software programs to determine body composition in dogs with an application to canine obesity research. Beagles and greyhounds were chosen for their differences in morphology and propensity to obesity. Whole body CT scans with regular intervals were performed on six beagles and six greyhounds that were subjected to a 28-day weight-gain protocol. The CT images obtained at days 0 and 28 were analyzed using software programs OsiriX, ImageJ, and AutoCAT. The CT scanning technique was able to differentiate bone, lean, and fat tissue in dogs and proved sensitive enough to detect increases in both lean and fat during weight gain over a short period. A significant difference in lean : fat ratio was observed between the two breeds on both days 0 and 28 (P < 0.01). Therefore, CT and advanced image analysis proved useful in the current study for the estimation of body composition in dogs and has the potential to be used in canine obesity research.
Evaluation of breed effects on n-3 PUFA metabolism with dietary flaxseed oil supplementation in dogs
2011, Purushothaman, Dharma, Brown, Wendy, Wu, Shubiao, Vanselow, Barbara
PUFA are important for human and animal health. To our knowledge, previous studies investigating the metabolism of PUFA in dogs have not examined breed differences. The aim of the present study was to evaluate the potential to elongate PUFA in two pure breeds of dogs. Plasma fatty acid composition (%) was measured in dogs during 3 weeks supplementation with flaxseed oil (57 % α-linolenic acid (ALA) and 17 % linolenic acid (LA)) at the rate of 100 ml/kg food following 4 months of feeding an identical standard basal diet. Plasma extracted at fasting state from five beagles and five greyhounds was analysed by GC. Plasma ALA, EPA and LA increased steadily and significantly from days 0 to 22 (P < 0·05); however, no significant breed differences were shown. Plasma DHA levels, on the other hand, showed no significant increase over time, but a significant breed difference was observed, with beagles having higher plasma level from day 0 (P = 0·002). This breed difference requires further investigation. Levels of ALA and EPA were still rising significantly between days 15 and 22, indicating that PUFA levels in plasma had not stabilised in 3 weeks. These findings together suggest that flaxseed oil could be a useful source of PUFA in dogs, especially ALA and EPA, and that breed differences may be important.
Dietary Flaxseed Oil Supplementation in Two Dog Breeds
2010, Purushothaman, Dharma, Brown, Wendy, Wu, Shubiao, Vanselow, Barbara
A nutritional trial aimed at flaxseed oil supplementation was performed to support a genetic project that is analysing the impact of essential fatty acids on gene expression in leucocytes. This preliminary study analyzed plasma fatty acid composition (%) following oil supplementation over time and measured the effect of breed.